1. Field of the Invention
The present invention relates to a processing system for recycling post-industrial-use plastic, i.e., a processing system for converting discarded manufacturing plastic waste into a resource.
2. Brief Description of the Prior Art
Plastic is not any one material. Rather it is a family of related materials with varying properties that can be engineered to meet the requirements of a broad range of applications. The success of a product often is dependent on matching the right plastic with the right properties to the right application.
The same is true when the material in question is a recycled plastic. As a result, there is a premium placed on the purity of post-use plastics. The more uniform the post-use plastics going in, the more predictable the properties of the recycled plastic coming out.
Coding the plastic allows sorting before recycling, ensuring that the recycled plastic is as homogeneous as possible. Plastic containers for consumer use come in a variety of different colors based on marketing considerations. The same plastic may be used in different colored containers and the same color containers may be formed of chemically different plastics. Hence it not possible to sort post-consumer-use containers into homogeneous groupings of plastic based on color.
The benefit of sorting the plastic has led a number of entities to develop coding systems which are not dependent on color, including the Society of the Plastics Industry (SPI), the Society of Automotive Engineers (SAE), the American Society for Testing and Materials (ASTM) and the International Standards Organization (ISO). Except where laws may require the use of a particular code, manufacturers have the option of selecting the coding system most appropriate for their product or of not using any coding system at all.
Post-use plastic, even homogenous recycled plastic, has low scrap value. Hence high labor costs make recycling uneconomic unless the segregation of the plastic into groups can be done quickly and inexpensively. Consumer plastic containers are typically marked with an SPI code and can be sorted manually. This method is slow, labor intensive, and expensive. Although separation machines exist, they are expensive and have a recovery rate of only 70-80%. The machines rely on sophisticated analytical equipment, precise manipulation and technical expertise.
In industry, plastic is used on goods to protect parts for shipping or manufacturing purposes. For example caps are placed on tubing to keep it from being accidentally contaminated and on wire looms to keep them from being damaged. Separators are used to keep parts from rattling, clips are used to hold parts together, etc. The goods are shipped from a parts supplier to an original equipment manufacturer or assembler, where the plastic guards are removed and the part used. From the standpoint of the end-point industrial user, the color of the plastic guard makes no difference.
Some of the plastic guards are marked with an SPI or some other code, others are not marked at all. Because of the low scrap value of plastic and the inconsistency or absence of marking, the end-point industrial user has no economic incentive to recycle the discarded articles. Hence most post-industrial-use plastic is burned or sent to a landfill, giving rise to a litany of serious, well-known environmental problems, including global warming and water pollution. In addition, disposal charges for the post-industrial-use plastic waste add to the original equipment manufacturer's or assembler's manufacturing costs. Such being the circumstances, there exists a great social demand favoring recycling of post-industrial-user plastic waste. It is to this need that the present invention is directed.